1. Field of the Invention
The present invention relates to a manufacturing method of a ceramic honeycomb structure, and more particularly, it relates to a manufacturing method of a ceramic honeycomb structure which has an excellent productivity and in which it is possible to manufacture the ceramic honeycomb structure having an excellent perpendicularity irrespective of a size of an outer diameter dimension of the ceramic honeycomb structure.
2. Description of Related Art
In various fields of chemistry, electric power, iron and steel, and the like, a honeycomb structure made of a ceramic material (the ceramic honeycomb structure) is employed as a support for a catalyst device to be used in an environmental countermeasure, recovery of specific substances and the like. Moreover, the ceramic honeycomb structure is also used as a filter for purification of an exhaust gas. Such a ceramic honeycomb structure has excellent heat resistance and corrosion resistance, and is employed in various use applications as described above. The honeycomb structure is a structure having partition walls with which a plurality of cells extending from one end surface to the other end surface are formed to become through channels of a fluid.
Heretofore, the honeycomb structure having an outer diameter dimension smaller than 150 mm has been manufactured by the following method. First, a kneaded material including a forming raw material is formed into a honeycomb-like shape, to obtain a formed honeycomb body. The formed honeycomb body is a cylindrical body in which the plurality of cells extending from the one end surface to the other end surface are formed with the partition walls. This formed honeycomb body is cut so that a length of the formed honeycomb body in a cell extending direction is larger than a length of a finished dimension, and furthermore, the formed honeycomb body is dried, to obtain the dried honeycomb body. Next, a finishing step is performed so that the length of the dried honeycomb body in the cell extending direction becomes the finished dimension, to obtain the finished dried honeycomb body. Next, the finished dried honeycomb body is fired, to obtain the honeycomb structure (see, e.g., Patent Document 1). Moreover, the honeycomb structure manufactured by such a method is inspected so as to judge whether or not an outer diameter dimension of the honeycomb structure satisfies an outer diameter dimension tolerance as a reference, and the honeycomb structure which has passed the inspection is shipped as a product.
On the other hand, when the honeycomb structure having an outer diameter dimension of 150 mm or more is manufactured, a step of separately preparing an outer wall is added sometimes (see, e.g., Patent Document 2). An example of the step of separately preparing the outer wall is a step of firing the finished dried honeycomb body, grinding an outer periphery of the obtained fired body, and coating a ground outer peripheral portion with an outer periphery coat to separately prepare the outer wall. The honeycomb structure having an outer diameter dimension of 150 mm or more will be called “the large honeycomb structure” sometimes.
Hereinafter, the above example of the manufacturing method of manufacturing the honeycomb structure by drying, finishing and firing the formed honeycomb body will be called “the manufacturing method by integral forming” sometimes. Moreover, the manufacturing method to which the step of separately preparing the outer wall is added will be called “the manufacturing method by outer periphery coating” sometimes. Furthermore, as a method of finishing step of end surfaces of the honeycomb structure, there is disclosed a method of correcting a posture of the honeycomb structure to perform the finishing step in this state, or the like (see, e.g., Patent Document 3).    [Patent Document 1] JP-A-2002-046856    [Patent Document 2] JP-A-3-275309    [Patent Document 3] JP-A-2006-231475